Enhancing fiber-optic sensing technique using a dual-core fiber

• US 20060171647A1
• Filed: 03/09/2006
• Published: 08/03/2006
• Est. Priority Date: 12/18/2002
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Baker, James R. Jr., Myaing, Mon, Thommey, Thomas, Norris, Theodore, Ye, Jing Yong
• Granted Patent: US 7,236,673 B2
• Time in Patent Office: Days
• US Class Current: 385/123
• CPC Class Codes: G01N 2021/6439 with indicators, stains, dyes, tags, labels, marks
• CPC Class Codes: G01N 2021/6484 Optical fibres
• CPC Class Codes: G01N 21/645 Specially adapted constructive features of fluorimeters
• CPC Class Codes: G01N 2201/0697 Pulsed lasers
• CPC Class Codes: G02B 6/02042 Multicore optical fibres
• CPC Class Codes: G02B 6/02047 Dual mode fibre G02B6/105 takes precedence
• CPC Class Codes: G02B 6/02357 Property of longitudinal structures or background material varies radially and/or azimuthally in the cladding, e.g. size, spacing, periodicity, shape, refractive index, graded index, quasiperiodic, quasicrystals
• CPC Class Codes: G02B 6/02366 Single ring of structures, e.g. "air clad"
• CPC Class Codes: G02B 6/02371 Cross section of longitudinal structures is non-circular

Abstract

An optical fiber for use in fiber optic sensing of a test sample includes a first core and a second core. The second core is generally coaxially disposed within the first core and is sized smaller than the first core. The second core is capable of delivering pulsed laser energy from the laser for nonlinear optical excitation of the test sample. Nonlinear optical feedback signals can then be collected in both the first core and second core for improved detection efficiency relative to conventional single-mode and multi-mode fibers.

Claims

1. An optical fiber for use in fiber optic sensing of a test sample, said optical fiber connectable to a laser outputting pulsed laser energy, said optical fiber comprising:

a first core; and

a second core generally coaxially disposed within said first core, said second core being sized smaller than said first core, said second core capable of receiving the pulsed laser energy from the laser for nonlinear optical excitation of the test sample.

2. The fiber according to claim 1 wherein said first core has a first radius and said second core has a second radius, said first radius being greater than said second radius.

3. The fiber according to claim 2 wherein said first core has a numerical aperture larger than that of said second core.

4-9. -9. (canceled)